Boat trailer



FIG. 1 is a top plan view of a boat trailer embodying my new design;

FIG. 2 is a right side elevational view thereof;

FIG. 3 is a left side elevational view thereof;

FIG. 4 is a front end elevational view thereof; and

FIG. 5 is a rear end elevational view thereof.

The ornamental design for a boat trailer, as shown.